The present invention relates to hand grips, and more particularly pertains to an improved hand grip for ambulation aids such as crutches, walkers, canes, outrigger skis, etc., adapted to reduce chronic fatigue, pain and damage to nerves, tendons, cartilage, bone and muscles frequently experienced by individuals who regularly use such ambulation aids. Typically, ambulation aids such as crutches employ hand grips of a substantially cylindrical shape, some of which include finger recesses similar to those found on bicycle hand grips. Such conventional grips are typically formed from a relatively hard rubber or plastic, although foam rubber covers or padding have been provided in an effort to enhance user comfort. Individuals employing ambulation aids on a daily basis fitted with such conventional grips experience potentially debilitating tissue damage for several reasons. First, conventional hand grips concentrate pressure on areas of the hand least suited for bearing such loads, such as the volar aspect of the palm and the adductor pollicis muscle located in the web of the hand between the thumb and forefinger. This undesirable load distribution results in the compression of the median, ulnar and palmar nerves, as well as the ulnar and palmar arteries. Such compression results in the restriction of blood flow and nerve entrapment syndromes, specifically, carpal tunnel syndrome. Prolonged excessive loading in the region of the adductor pollicis muscle can result in permanent injury to the proper palmar digital nerves of the thumb and the flexor pollicis longus tendon. Second, conventional grips do not properly axially align the hand and wrist with the ulna and radius bones of the arm. Rather, conventional grips promote dorsal flexation of the wrist, resulting in increased tensional stress on the tendons, nerves and blood vessels on the palmar side of the wrist, while at the same time forcing the wedge-shaped anticular disc of cartilage separating the radius and ulna bones of the arm from the lunate and scaphoid bones of the wrist too far into the interface between the arm and wrist. This compression of the disc forces the bones apart and places compressive stress on the radial, medial and ulnar nerves, blood vessels and ligaments. Misalignment of the wrist and arm is particularly exacerbated by the typical use of ambulation aids in a manner which disposes the elongated support member at an acute angle to the vertical. Individuals paralyzed from the waist down employ a technique known as "gaiting" in order to ambulate using crutches. This technique places the entire weight of the user on the hands, while the crutch shafts are disposed at an acute angle to the vertical. Such individuals are particularly susceptible to permanent debilitating injury to the hands and wrists.
An individual, upon being fitted with conventional ambulation aids such as crutches, typically experiences an initial period of great discomfort and fatigue. Due to natural strengthening of muscles, the individual then generally experiences a short term reduction of pain and fatigue. Over the long term, however, the degeneration of nerves, tendons and cartilage in the hands and wrists of the individual results in increasing fatigue, loss of strength, and pain. Many such individuals actually become unable to continue to employ crutches, and are forced into wheelchairs.
Accordingly, it is highly desirable to distribute forces in a manner such that a major portion of the force is born by muscles, rather than nerves, blood vessels and tendons. Muscles are natural load bearing cushions in compression. Their resilience and load bearing capacity are alterable by voluntary or involuntary contraction which causes their cross-section to thicken.